(*
 * Copyright (c) 2017 - present Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *)
open! IStd

(* version macros like kCFCoreFoundationVersionNumber_iOS_9_0 are
   tied to specific float values, e.g. 1240.1.
   To be found in CoreFoundation/CFBase.h *)

type machine_readable_version = float
type human_readable_version = string
type t = machine_readable_version * human_readable_version

let version_numbers : t list =
  [(478.23, "2.0");
   (478.26, "2.1");
   (478.29, "2.2");
   (478.47, "3.0");
   (478.52, "3.1");
   (478.61, "3.2");
   (550.32, "4.0");
   (550.38, "4.1");
   (550.52, "4.3");
   (675.00, "5.0");
   (690.10, "5.1");
   (793.00, "6.1");
   (847.20, "7.0");
   (847.24, "7.1");
   (1140.1, "8.0");
   (1141.14, "8.1");
   (1142.16, "8.2");
   (1144.17, "8.3");
   (1145.15, "8.4");
   (1240.1, "9.0");
   (1241.11, "9.1");
   (1242.13, "9.3");
   (1280.38, "9.4");
   (1348.0, "10.0");
   (1348.22, "10.2");]

let sort_versions versions =
  let compare (version_float1, _) (version_float2, _) =
    Float.compare version_float1 version_float2 in
  List.sort ~cmp:compare versions

let version_of number_s : human_readable_version option =
  let epsilon = 0.001 in
  let rec version_of_aux version_numbers number =
    match version_numbers with
    | (version_n, version_s) :: (next_version_n, next_version_s) :: rest ->
        if (number -. version_n) < epsilon && (number -. version_n) > -. epsilon then Some version_s
        else if (number >= (version_n +. epsilon) && number <= (next_version_n -. epsilon))
        then Some next_version_s
        else version_of_aux ((next_version_n, next_version_s) :: rest) number
    | [version_n, version_s] ->
        if number >= version_n then Some version_s
        else None
    | [] -> None in
  let number_opt =
    try Some (float_of_string number_s)
    with Failure _ -> None in
  match number_opt with
  | None -> None
  | Some number -> version_of_aux (sort_versions version_numbers) number

let pp_diff_of_version_opt fmt (expected, actual) =
  let option_to_string opt = Option.value ~default:"" opt in
  Format.fprintf fmt
    "Expected: [%s] Found: [%s]" (option_to_string expected) (option_to_string actual)